Slitter for metal lath



Sept. 19, 1933. w. c. CORYELL 1,927,542

SLITTER FOR METAL LATH Filed June 12, 1930 Q rv-n" 1 Patented Sept. 19, 1933 uN TEo STATE-ES PATENT OFFICE.

SLITTER, FOR LATH William C. Col-yell, Youngstown, Ohio, assignor to United States Gypsum Company, Chicago, Ill., a corporation of Illinois" Application June 12, 1930. seri ljno. 460,694

:2 Claims. (01. 16 -436) This invention relates to metal lath slitting disks of the type having radial notches out in the sides and opening through the edges thereof, so that when asheet to be slitted is passed between I a pair of such disks mounted on separate shafts with their peripheral portions in over-lapping relation, the sheet is slitted atlongitudinallyspaced intervals and a tie piece is left remaining between the ends of each adjacent pair of slits, a gang of slitting disks usually being mounted on each shaft so that a plurality. of rowsv of slits are formed in a single operation, andthe disks usually beingarranged relativeto one another so that the slits in 1 the respective rows are cut in staggered relation.

l-leretofore, in slitting disks of; the foregoing type, it has beenthe general practice to form the notches of uniforln width throughout their lengths, i. e., from the edges of the disksto the inner ends of the notches, and since it is necessary at more orsless frequentintervals-to grind away peripheral portions .of the disks in orderto preserve sharp cutting ed es thereon, the resulthas been, due to the decreased diameter of the disks resultingfrom grinding away of the peripheral portions thereof, that the tie pieces formed with ground disks have remained of the same length as the tie pieces formedwith new or. unground disks, while the slits formed with ground disks have been shorter than the slits formed with new or unground disks, the length of the slits obviously becoming shorter and shorter as the diame ters of the disks are progressively decreased by repeatedgrindings.

It is desirable of course-to secure as much service as possible from a set of disks, and to 1113111? tain practicable proportions between the lengths of the slits and the lengths of the tie pieces, and ..it is the object of the present invention to provide a slitting disk with notches shaped in a novel manner to accomplish these desirable purposes, a disk provided with notches according to the pres ent invention being capable of considerable re- ;grinding and use after it has been ground down to a diameter which would render one of the disks now in general use unfit for continued service, and the tie pieces formed by the present disk being progressively decreased in length with a proporltionate less decrease in the lengths of the slits as the diameter of the disk is decreased.-

In the accompanying drawing, wherein is illus- "comparison with a prior slitting disk:'-+

Figurel is a side elevation of the present disk.

Figure 2 is an edge View of the present disk.

Figure 3 is a section on the line 33 of Fig. 1.

Figure l is an enlargedfragmentary edge View of the present disk before having been subjectedto grinding.

Figure 5 is a view similar to Fig. 4 illustrating the disk after grinding. V

Figure 6 is an enlarged fragmentary side elevation of the present disk.

Figure 7 is a fragmentary side elevation on the same scale as Fig. 1 of a prior disk. s Figure 8 is an enlarged fragmentary side elevation of the prior disk.

Figures 9 and 10 are plan views of sheets slitted by new and ground disks, respectively, having notches according to the present invention; and

Figures 11 and 12 are plan views of sheets slitted by new and ground priordisks, respectively.

Referring in detail first to Figs. 7 and 8 of the .75 drawing which are illustrative of a well known prior slitting disk, it will be observed that the disk, designated generally as a, has radial notches 10 formed in the opposite side faces thereof at evenly spaced intervals circumferentially, and that said notches are of uniform width throughout their lengths, i. e., from the outer edge of the disk, through which they open, to their inner. ends.

As heretofore stated, and as is fully understood by those skilled in the art of producing slitted' metal lath, it is usual to mount a gang of the disks a on each of a pair of shafts with spacers between the respective disks, and to disposethe disks of the two gangs or setswith their marginal portions inintermeshed relation, whereby the edges of the disks cooperate to shear parallel rows of slits in a sheet passed between the two gangs or sets of disks, the length of the slits being determined by the circumferential spacing of the notches 10 andthe length of the tie pieces left remaining between the ends of each adjacent pair of slits in a row being determined by the width of the notches 10. Notches 10 are formed in both sides of the disks and the notches in one side are preferably staggered or located bet-ween the notches in the other side, so that in the slitted sheet the slits and the tie pieces are disposed in staggered relation. When the edges of the disks become dull the shaft with its disks is removed from the slitting machine, put on the centers of a grinding machine, and the disks are ground as a cylinder while the shaft and the cutters are has been effected, the distance between adjacent notches 10 at the periphery of the disk is a maximum. Consequently, the slits 11 formed in a sheet 12 by a new disk a are or" maximum length as indicated in Fig. 11 of the drawing. On the other hand, when the disk has been ground down to a reduced diameter, as illustrated by the broken line 14 in Figs. .7 and 8 for example, the distance between adjacent notches 10 is shorter, with the result, as shown in Fig. 12, that the slits ll formed in a sheet 12 by the ground disk are shorter than the slits 11 formed by the new or unground disk. However, due to the uniform width of the notches 10, the tie pieces 13 left remaining between the ends of each adjacent pair of slits remains the same in each instance.

With prior slitting disks of the type shown in Figs. 7 and 8, which disks in practice and when new are approximately nine inches in diameter, it has been found that after a maximum of approximately three eighths or" an inch has been ground away from the peripheral portion thereof, the length of the slits formed by the disk become of such less length than the slits formed by the disk when new as to forbid use of the disk if it is further ground away and if satisfactory lath is to be produced. Hence, when a prior disk is ground down to a diameter of approximately three-fourths of an inch less than its original diameter, the disk is discarded as unfit for further service.

According to the present invention, the notches 10 in the disk A are formed by double non-radial cuts of a milling cutter, as distinguished from the single radial cut of such a cutter employed to form the notches 10 in the prior disk. Instead of being radial, the double cuts employed to form the notches 10 in the present disk are made in directions slightly oblique to a radial line, the obliquity of the cuts being equal and opposite, respectively, as best shown in Fig. 6. In other words, the present notches 10 are of decreasing width towards the center of the disk, and in a present disk A of the same diameter as a new prior disk a, the width of the present notches 10 at the periphery of the disk is somewhat greater than the width of the prior notches 10, while adjacent to their inner ends, the width of the present notches is somewhat less than the width of the prior notches 10. Hence, While the distance between adjacent edges of adjacent notches of the present disks decreases towards the center of the disk, such decrease is relatively slight as compared with the decrease in the distance between the notches of the prior disk in the same direction. Accordingly, when the present disk is new,-the slits 11 and the tie pieces 'stantially maintained.

13 formed thereby in a sheet 12 all are of maximum length, as illustrated in Fig. 9. On the other hand, when the diameter of the present disk is reduced by grinding, both the slits and the tie pieces formed thereby are reduced in length as illustrated at 11, 13, respectively, in Fig. 10 of thedrawing. However, the reduction in length of the slits and the tie pieces is only relatively slight, and the original proportion between the lengths of the slits and the tie pieces is sub- Therefore, satisfactory commercial lath may be produced with the present cutters after they have been ground down to a diameter considerably less than the minimum diameter at which it has been found practicable to employ a prior disk. In fact, it has been found that satisfactory lath may be produced by the present disk when as much as five-eighths of an inch has been ground from the periphery of the disk, which means that the diameter of the present disk may be reduced approximately one and one-quarter inches, as compared with the maximum reduction of three-fourths of an inch in the diameter of the prior disk, before the respective disks must be discarded, the broken line 15 in Fig. 6 illustrating the approximate extent to which the present disk maybe reduced in diameter.

As there can be quite an assortment of notches cut in the'side of the disk having a general radial direction, and having a longitudinal taper with the wider end of the notch at the outer periphery, and the narrower end of the notch toward the center, we wish it understood that radial be be understood in a general sense.

Without further description it is thought that the features and advantages of the invention will be readily apparent to those skilled in the art, and it will of course be understood that changes in the form, proportion and minor details of construction may be resorted to, without departing from the spirit of the invention and scope of the appended claims.'

I claim:-- Y

1. A metal lath slitting disk having notches in a side thereof opening through the outer edge of the disk, said notches having edges extending along radii of the disk.

2. A metal lath slitting disk having elongated tapered notches equally spaced along the periphery at the sides, the notches on opposite sides being in staggered relation, the bases of the notches being in the circumference, the apices of the notches being towards the center, and the edges of the notches extending along radii of the disk.

WILLIAM C. CORYELL. 

